Sodium Benzoate

What it is and how it works

Sodium benzoate is conjugated with glycine in the liver and kidney to form hippurate, which is rapidly excreted in the urine. Each mole removes one mole of nitrogen, providing an alternative pathway for waste nitrogen excretion when the urea cycle is impaired.

Indications

Hyperammonaemia due to urea cycle disorders and other inborn errors of metabolism, acute (intravenous, often with sodium phenylacetate) and long-term (oral); also used in non-ketotic hyperglycinaemia.

Dosage and administration (summary)

Dosing is individualised by the metabolic specialist according to body weight or surface area and plasma ammonia and amino acid levels, used together with protein restriction and other measures; intravenous doses are given as a loading dose followed by maintenance infusion via a central line.

Contraindications

Hypersensitivity to sodium benzoate.

Warnings and precautions

Monitor plasma ammonia, electrolytes and acid–base status; the high sodium load may cause fluid retention in cardiac or renal impairment. Avoid in neonatal hyperbilirubinaemia where possible because benzoate may displace bilirubin from albumin, and avoid concomitant valproate, which can increase ammonia; nausea and vomiting are common.

Pregnancy

Use in pregnancy only if clearly necessary under specialist supervision.

Storage and supply

Store below 25 °C.

Source: reference summary prepared from the EU SmPC/EPAR, BNF and WHO Model Formulary. The approved product information in Iran governs.